When I looked at that series, something didn’t seem to add up, and doesn’t. Those four percentages are shown as separate categories, which implies they are exclusive. But, 40% + 25% + 23% + 20% = 108%. That’s bull dung.

Something is wrong with the raw data. Before you plot percentages you need to check that they total to a hundred percent. (You could have the named percentages total to less than a hundred, if you left out a miscellaneous or other category though).

PowerPoint is set up to automatically scale the total from them to fill a circle on a single pie chart or donut chart, so it won’t object to showing something silly like this. If you tried to plot them on a single chart, you might be more likely to check them. When you saw that 25% did not fill 90 degrees, you would ask what is wrong.

Perhaps there really are people who use a train or bus and they shop while commuting. Or, maybe there are people who grab a sandwich and have dinner while they are either shopping or commuting. The charts should show what is really happening.

About Me

This blog is about public speaking. The author is Richard I. Garber, ACS, a Toastmaster. From July 2008 to June 2010 he was Vice President-Education for Capitol Club Toastmasters in Boise, Idaho. Opinions expressed on this blog are those of the author alone, and are not the official positions of Toastmasters International, etc.
Richard is retired. He has over twenty years of experience as a consultant on failure analysis (figuring out why things busted or rusted) and a Ph.D. in Metallurgical Engineering & Materials Science.
His email is r_i_garber at hotmail.com

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We don’t necessarily believe what we write, and neither should you. Information furnished to you is for topical (external) use only. This information actually may not be worth any more than what you paid for it (nothing). The author may not even have been either sane (or sober) when he wrote it down and posted it. Don’t worry, be happy.